Studies of the Lichen Symbiosis

Scott, G. D.

doi:10.1111/j.1469-8137.1960.tb06232.x

Cited by 39 publications

(27 citation statements)

References 6 publications

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“…However, the moisture condition of the moss could change the nutrient supply and exchange between moss and associated cyanobacteria. Scott (1960) suggested that not only nutrients, but also light and moisture could affect the balance and rates of nutrients exchanged between the symbiotic partners in lichen symbioses, upsetting the relationship between them.…”

Section: Abiotic Controls Of N2 Fixation In Moss-cyanobacteria Associmentioning

confidence: 99%

“…However, in the lichen symbiosis for instance, the balance between the exchange of nutrients seems to be not entirely mutually beneficial, but rather depends on the nutrient demands of the partners (Johansson et al, 2011). Over 50 years ago, Scott (1960) reported that variations in the supply of nutrients, light, and moisture could upset the symbiotic balance between the mycobiont and photobiont in lichen symbioses. The growth of both symbionts is controlled by moisture levels and availability of N and C, resulting in a delicate balance between the partners (Scott, 1960).…”

Section: The Ecology Of Moss-cyanobacteria Associations—what Relationmentioning

confidence: 99%

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Moss-cyanobacteria associations as biogenic sources of nitrogen in boreal forest ecosystems

Rousk¹,

Jones²,

DeLuca³

2013

Front. Microbiol.

130

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The biological fixation of atmospheric nitrogen (N) is a major pathway for available N entering ecosystems. In N-limited boreal forests, a significant amount of N2 is fixed by cyanobacteria living in association with mosses, contributing up to 50% to the total N input. In this review, we synthesize reports on the drivers of N2 fixation in feather moss-cyanobacteria associations to gain a deeper understanding of their role for ecosystem-N-cycling. Nitrogen fixation in moss-cyanobacteria associations is inhibited by N inputs and therefore, significant fixation occurs only in low N-deposition areas. While it has been shown that artificial N additions in the laboratory as well as in the field inhibit N2 fixation in moss-cyanobacteria associations, the type, as well as the amounts of N that enters the system, affect N2 fixation differently. Another major driver of N2 fixation is the moisture status of the cyanobacteria-hosting moss, wherein moist conditions promote N2 fixation. Mosses experience large fluctuations in their hydrological status, undergoing significant natural drying and rewetting cycles over the course of only a few hours, especially in summer, which likely compromises the N input to the system via N2 fixation. Perhaps the most central question, however, that remains unanswered is the fate of the fixed N2 in mosses. The cyanobacteria are likely to leak N, but whether this N is transferred to the soil and if so, at which rates and timescales, is unknown. Despite our increasing understanding of the drivers of N2 fixation, the role moss-cyanobacteria associations play in ecosystem-N-cycling remains unresolved. Further, the relationship mosses and cyanobacteria share is unknown to date and warrants further investigation.

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Section: Abiotic Controls Of N2 Fixation In Moss-cyanobacteria Associmentioning

confidence: 99%

Section: The Ecology Of Moss-cyanobacteria Associations—what Relationmentioning

confidence: 99%

Moss-cyanobacteria associations as biogenic sources of nitrogen in boreal forest ecosystems

Rousk¹,

Jones²,

DeLuca³

2013

Front. Microbiol.

130

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“…Exceptional conditions, e.g. a long-term exposure to excessive moisture (Scott, 1960) or applications of N-rich fertilizers (Kauppi, 1980) disrupted the association between the fungal and algal components and even led to the independent growth of algal cells in the lichen thallus. Barashkova (1960) reported on the same phenomenon in her experiments in which slices from podetia of Cladina rangiferina on an agar medium were treated with Knop's nutrient solution.…”

Section: mentioning

confidence: 99%

Ethylene produced by the lichen Cladina stellaris exposed to sulphur and heavy‐metal‐containing solutions under acidic conditions

Kauppi

Garty

1998

New Phytologist

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Podetia of the terricolous lichen Cladina stellaris (Opiz) Brodo, collected in an unpolluted rural area in N. Finland, were wetted with either H # O, diluted acidic solutions of H # SO % , HNO $ and NaHSO $ , simulating acidic rain, or the following salts :The samples were further exposed to combined treatments in both acidic solutions, simulating acidic rain, and heavy metal salts in solution. Lichen samples wetted with H # O at pH 6n8, diluted solutions of H # SO % , HNO $ or a mixture of these two acids produced low concentrations of endogenous ethylene. The application of NaHSO $ greatly increased the production of ethylene. The application of KCl induced a higher rate of ethylene production than the application of K # SO % solutions. The application of Cu-containing solutions enhanced the production of ethylene. The influence of Zn was smaller than that of Cu. Iron was the most effective heavy metal to promote the production of ethylene : very high ethylene concentrations were detected upon the application of FeCl # . Combined treatments in H # SO % or H # SO % jHNO $ followed by either FeCl # or FeSO % , yielded higher concentrations of ethylene than the same treatments in a reversed order. The role of Fe ions in the production of ethylene is discussed in reference to previous works dealing with ethylene production in higher plants, fungi and algae.

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“…Drying down of the top surface would leave the water film intact on the lower surface for a longer period and cause the period of low NPR to extend to lower thallus water contents. Support is thus given to the proposal of Scott (1960) that lichen medullas may be important for gas exchange.…”

Section: Discussionmentioning

confidence: 99%

“…Lichens in the family Stictaceae possess either cyphellae or pseudocyphellae on the underside and in the past these have been suggested to have a role in gas exchange although, again, no actual evidence is available (Ahmadjian and Hale, 1973;Henssen and Jahns, 1974;Hale, 1974;Rundel, Bratt and Lange, 1979). Einally, Scott (1960) proposed from growth studies that gas exchange in Peltigera praetextata occurred entirely through the fungal medulla and that excess water would diminish the rate of exchange.…”

Section: Introductionmentioning

confidence: 99%

Carbon Dioxide Exchange in Lichens.

1981

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SUMMARYCarbon dioxide (COg) exchange of Sticta latifrons Rich, was studied using an infrared gas analyzer. Slight differences in the relationship between net photosynthetic rate (NPR) and water content were found when thalli were dried by using air directed solely onto the upper or lower surfaces. Further studies using a simple split chamber which allowed separate analysis of the CO2 exchange of upper and lower thallus surfaces demonstrated that the vast majority of COg exchanged through the lower surface. The results provide strong circumstantial evidence for the suggestion that cyphellae act as air pores and the possible importance of such pores in the water relations of the species is discussed.

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Studies of the Lichen Symbiosis

Cited by 39 publications

References 6 publications

Moss-cyanobacteria associations as biogenic sources of nitrogen in boreal forest ecosystems

Moss-cyanobacteria associations as biogenic sources of nitrogen in boreal forest ecosystems

Ethylene produced by the lichen Cladina stellaris exposed to sulphur and heavy‐metal‐containing solutions under acidic conditions

Carbon Dioxide Exchange in Lichens.

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